CN-121983470-A - Linear electromagnetic relay switching-on speed control method of self-adaptive stray magnetic field

CN121983470ACN 121983470 ACN121983470 ACN 121983470ACN-121983470-A

Abstract

The application discloses a switching-on speed control method of a self-adaptive stray magnetic field linear electromagnetic relay, which comprises the steps of S1 detecting current of the linear electromagnetic relay in real time, and carrying out current limiting control on the linear electromagnetic relay when the current falls to a critical current value after reaching a peak value, S2 obtaining a current limiting value according to a correction coefficient, initial limiting and the current peak value, and controlling the current to be near the current limiting value, S3 updating the current limiting coefficient until the current limiting coefficient is reduced to a preset minimum coefficient when detecting current limiting failure, and S4 limiting the current to a lower value by a power supply according to the preset minimum coefficient in a holding stage. The application can enhance the reliability and safety of the linear electromagnetic relay under the stray magnetic field, has small modification range and less additional materials for the existing products, is mainly realized by a control strategy and a small number of general device configurations, and is convenient for large-scale production and assembly after modification.

Inventors

WANG RUMENG
FU XIANGYU
YANG YONG
ZHANG MING

Assignees

华中科技大学

Dates

Publication Date: 20260505
Application Date: 20260212

Claims (9)

1. A method for controlling the closing speed of a linear electromagnetic relay with a self-adaptive stray magnetic field is characterized by comprising the following steps: The method comprises the steps of S1, detecting current i of a linear electromagnetic relay in real time, and performing current limiting control on the linear electromagnetic relay when the current reaches a peak value i max and then is detected to fall to a critical current value i cv ; S2, obtaining a current limiting value i ref according to the correction coefficient alpha, the initial limit k0 and the current peak value i max , and controlling the current to be near the current limiting value i ref ; s3, when the current limiting failure is detected, updating the current limiting coefficient k until k is reduced to a preset minimum coefficient k min ; s4, in the holding stage, the power supply limits the current to a lower value according to a preset minimum coefficient alpha k min .
2. The method for controlling the closing speed of the linear electromagnetic relay according to claim 1, wherein in step S1, when the current is detected to drop to the critical current value i cv , the current limitation control is performed on the linear electromagnetic relay by turning off the MOSFET switching tube.
3. The method for controlling the closing speed of the linear electromagnetic relay according to claim 1, wherein in the step S2, the current limiting value i ref =α×k0×i max is present, and the correction coefficient alpha is determined by a current peak value i max .
4. The method for controlling switching-on speed of linear electromagnetic relay according to claim 1, wherein in step S2, a hysteresis current controller is used to control the current to a value near a current limit value i ref , specifically, when i ref When i > H, MOSFET is turned on, current i rises, when i When i ref > H, the MOSFET is turned off, the driving voltage is reduced to zero, and the current i drops, wherein H is the hysteresis width.
5. The method for controlling the closing speed of a linear electromagnetic relay according to claim 1, wherein in step S3, the current limiting coefficient k is decreased by a fixed value Δk every time it is updated.
6. The method for controlling the closing speed of a linear electromagnetic relay according to claim 5, wherein k is n =（k n 1 Δk), n is the number of updates, and the fixed value Δk is 0.2.
7. The method for controlling the closing speed of a linear electromagnetic relay according to claim 1, wherein in step S3, the minimum coefficient k min is 0.35.
8. The method for controlling the closing speed of the linear electromagnetic relay according to claim 1, wherein in the step S4, the lower value is 0.4A.
9. The method for controlling the closing speed of the linear electromagnetic relay according to claim 1, wherein the current limit failure is determined if the coil current cannot be maintained near the current limit reference value i ref and continuously decreases under the condition of continuously applying the driving voltage after the current limit control is started.

Description

Linear electromagnetic relay switching-on speed control method of self-adaptive stray magnetic field Technical Field The application belongs to the field of electromagnetic relay control, and particularly relates to a self-adaptive stray magnetic field linear electromagnetic relay closing speed control method which is used for inhibiting the closing speed of a linear relay armature under a random stray magnetic field environment. Background Electromagnetic relay belongs to magnetic electronic control device, and uses electromagnetic acting force (containing moment) to drive armature movement so as to implement connection and conversion of circuit, and can be extensively used in automatic control, relay protection and communication system. The device is sensitive to an external magnetic field, is easy to be interfered under the action of a stray magnetic field and is abnormal. In order to improve the anti-jamming capability, the driving current is usually increased, but the collision speed between the armature and the contact is too high due to the increase of the closing speed. For example, a conventional linear electromagnetic relay has a switching-on speed of about 1.5m/s at rated current, and a speed increased by about 120% and a collision kinetic energy increased by about 384% when the current is required to be driven to 3.3m/s in a stray magnetic field resistance. Excessive collision speed will cause armature bounce and contact arcing, thereby affecting product life and reliability and safety of the system. Although various control methods aiming at the bouncing of the electromagnetic relay exist, the electromagnetic relay bouncing control method is generally difficult to realize in the stray magnetic field environment, on one hand, the magnetic core is saturated to different degrees due to the external stray magnetic field, so that the inductance-displacement relation of the driving coil is offset or even distorted, the strategy of displacement prediction and collision inhibition based on the relation is not applicable, on the other hand, the stray magnetic fields with different intensities and directions can change the equivalent magnetic resistance and counter electromotive force characteristics of the actuator, so that the voltage-current curve is remarkably drifted along with the working condition, and the displacement or speed prediction model constructed based on the voltage and current signals is disjointed with the real motion state. Meanwhile, the method for carrying out batch-to-batch (R2R) self-adaptive adjustment by depending on multi-time action data is limited by time-varying and scene migration characteristics of a stray magnetic field, parameter updating is difficult to stably converge and is easy to mismatch, the prediction control taking an artificial neural network as a core needs to cover large-scale training data under all working conditions, the introduction of the stray magnetic field further increases input dimension and variable combination, the geometric level of data and calculation amount is increased, and the real-time performance and cost constraint on engineering are difficult to meet. In addition, introducing magnetic field measurement into the control system increases the sensing link and calibration process, improves the complexity and economic cost of the system, and introduces a new error source to affect the reliability. For the above reasons, it is highly desirable to provide a control method capable of effectively inhibiting the bouncing of an electromagnetic actuator under the condition of a stray magnetic field, which does not depend on direct measurement of the magnetic field, can adaptively characterize and compensate the variation of the stray magnetic field by using the electrical parameters available to the device, and effectively restricts the closing end speed and the collision kinetic energy on the premise of not remarkably increasing the complexity and the cost of hardware, thereby improving the reliability and the safety of the electromagnetic relay. Disclosure of Invention Aiming at the defects of the prior art, the application aims to provide a method for controlling the closing speed of a linear relay, which does not need a magnetic field sensor and can adapt to the intensity of a stray magnetic field, so that the linear relay can realize closing with low collision speed in the range of the whole stray magnetic field and maintain reliability. The application provides a method for controlling the closing speed of a linear electromagnetic relay with a self-adaptive stray magnetic field, which comprises the following steps: The method comprises the steps of S1, detecting current i of a linear electromagnetic relay in real time, and performing current limiting control on the linear electromagnetic relay when the current reaches a peak value i max and then is detected to fall to a critical current value i cv; S2, obtaining a current limiting value i ref